iOS/Android (soon): Clipping coupons is a great way to save money on groceries, as long as you're willing to put in the time. Milk automatically finds and applies coupons for everything you're buying, so you get all the discounts automatically—with nothing but a single tap on your phone.

Here's how it works: You need a rewards card for the store in question (like Kroger or Ralph's), and you need to register an online account for that card. Those online accounts allow you to "clip" online coupons to your card, then just scan the card at checkout to get the discounts. Milk automates this entire process by applying all the available coupons to your card in one tap. That way, for every item in your cart that has a coupon available, you automatically get the discount, without doing any extra work. Once you've set it up, the process works like this:

Go to the grocery store and fill up your cart with whatever you're buying. You can browse coupons in the Milk app if you want, but you don't have to—just go about your shopping as normal.

Tap the big "Update Coupon" button in Milk for the store you're currently shopping at.

I tested it last night, on a relatively small shopping trip—just a couple items—and I saved $5 without even trying. That's pretty awesome.

Sure, you may not be able to get as deep a discount as if you were extreme couponing, but for most of us—who ignore coupons entirely because they're just too much work—this is a great way to effortlessly save a few bucks. It literally only takes one tap on your phone for every trip you take.

Milk is free for the first three months, and then costs $9.99 a year after that (or you can buy in monthly installments). It seems like a lot, but considering it saved me half of that on only one trip, it's well worth the price—especially if the alternative is being too lazy to use coupons at all.